Play+Soft was developed by Maurizio Fontanilli, designed by Harri Koskinen, in collaboration with Reggio Children over the course of a four-year, pedagogy-driven, design process. But any process that results in giant kid-sized Tetris blocks to play with, in both 2-D and 3-D, is on the right track.
See all the 3D shapes kids can build with it at Daddytypes. Via Kotaku & Wonderland.